JP2008031511A - Method for producing hydrophilic oil-repellent article - Google Patents

Abstract

An object of the present invention is to provide a method for producing an article, which can impart hydrophilic oil repellency to the surface of the article by a relatively simple process and has good durability of the hydrophilic oil repellency.
The surface of an article to be treated made of a material selected from the group consisting of glass, ceramics, and plastics has (A) perfluorocarbon, (B) oxygen atoms, C—H bonds, and halogen atoms. A method for producing an article comprising a step of forming a film on a surface of the article to be treated by performing a discharge treatment in an atmosphere containing an oxygen-containing compound that does not have any of them.
[Selection figure] None

Description

  The present invention relates to a method for producing an article having hydrophilic and oil repellency on its surface.

Many surface modifiers that impart hydrophilic oil repellency to the surface of an article have been proposed in order to make it difficult for dirt to adhere to the surface of the article and to easily remove the dirt by washing with water. Specifically, the following Patent Document 1 discloses a substrate to be treated using a copolymer of a fluorine-based vinyl monomer having a fluoroalkyl group and a cationic, anionic, and nonionic vinyl monomer as a surface modifier. A method of imparting antifouling property and antifogging property by applying to the surface of the substrate and forming a hydrophilic oil-repellent layer on the surface of the substrate is disclosed.
Patent Document 2 below discloses a silane composed of a fluoroalkyl silicone oligomer in which a fluoroalkyl group and a hydrophilic morpholino group are introduced into vinyl siloxane in order to chemically bond a substrate to be treated and a hydrophilic oil-repellent layer. A method of forming a hydrophilic oil-repellent layer on the surface of a substrate by applying a coupling agent to the substrate to be treated is disclosed.
Each of the methods described in Patent Documents 1 and 2 requires a liquid phase coating process and a drying process.

On the other hand, as a method for imparting antifouling properties to the surface of an object to be processed by a method that does not rely on liquid phase coating, for example, in Patent Document 3 below, plasma is applied to an antireflection film containing silicon in oxygen gas or argon gas The surface of the antireflection film is activated by the treatment, reacts with moisture of the residual gas component to form silanol groups at a high density, and then the fluorine-containing organosilicon compound is vacuum deposited to prevent high adhesion. A method for forming a dirty layer (water / oil repellent film) is described.
Patent Document 4 listed below discloses a method of forming an antifouling film (water / oil repellent film) on a substrate by using a perfluorocycloalkane having a perfluoroalkyl group by a plasma polymerization method. .
JP 2002-105433 A JP-A-9-241331 Japanese Patent Laid-Open No. 2005-301208 JP 2001-072921 A

The methods described in Patent Documents 1 and 2 are complicated because they require a liquid phase coating step and a drying step. In addition, the layer formed by the method described in Patent Document 1 is inferior in adhesion to the substrate surface and has a problem in durability.
In the methods described in Patent Documents 3 and 4, since the film formed on the surface of the object to be processed has water and oil repellency, the oil component can be prevented from adhering. It is difficult to remove the oil component.

  The present invention has been made in view of the above circumstances, and can produce a hydrophilic and oil-repellent material on the surface of the article with a relatively simple process, and the article can be manufactured with good hydrophilic and oil-repellent durability. Provide a method.

  In order to solve the above-mentioned problems, the method for producing an article of the present invention comprises (A) perfluorocarbon and (B) oxygen on the surface of an article to be treated made of a material selected from the group consisting of glass, ceramics and plastic. Having a step of forming a film on the surface of the article to be treated by performing a discharge treatment in an atmosphere containing an oxygen-containing compound having atoms and having neither a C—H bond nor a halogen atom. Features.

The (A) perfluorocarbon preferably has a carbon-carbon double bond.
The (B) oxygen-containing compound is preferably at least one selected from the group consisting of oxygen, ozone, carbon dioxide, water, nitric oxide, nitrogen dioxide, sulfur dioxide and sulfur trioxide.
The (A) perfluorocarbon is preferably tetrafluoroethylene or hexafluoropropylene, and the (B) oxygen-containing compound is preferably oxygen.
The film thickness is preferably 2 μm or less.
The contact angle of water in the membrane is preferably 40 ° or less, and the contact angle of n-hexadecane is preferably 25 ° or more.

  According to the present invention, an article having a hydrophilic and oil-repellent surface and a good durability of the hydrophilic and oil-repellent can be obtained by a relatively simple process.

<Processed article>
The article to be treated in the present invention has a surface (surface to be treated) made of a material selected from the group consisting of glass, ceramics, and plastic. A plurality of portions having different materials may exist on the surface of one article.
Specific examples of the glass include soda glass, lead glass, and borosilicate glass.
Specific examples of plastics include polyolefins such as polyethylene and polypropylene; polyvinyl chloride; polycarbonates; polyesters; polyethers; polyamides; polyimides, polyvinyl alcohols, polyurethanes, polycelluloses, polytetrafluoroethylenes, ethylenetetrafluoroethylene copolymers; Polychlorotrifluoroethylene; polyvinylidene fluoride; polyvinyl fluoride.
Specific examples of the ceramic include oxide ceramics such as alumina and zirconia; hydroxide ceramics; carbide ceramics such as silicon carbide; carbonate ceramics; nitride ceramics such as silicon nitride; halide ceramics; Examples thereof include phosphate ceramics.
The shape of the article to be processed is not particularly limited. Examples of the shape include a sheet shape, a film shape, a flat plate shape, a hollow fiber shape, a cylindrical shape, a container shape, a rod shape, a spherical shape, a block shape, a fiber shape, and a woven fabric shape. Among these, a sheet shape, a film shape, and a flat plate shape are preferable.
When the article to be treated is further processed into a final product, the film according to the present invention may be formed after the forming process. If the film is not broken during the forming process, the film is formed. You may give a shaping | molding process later.

<(A) Perfluorocarbon>
The perfluorocarbon used in the present invention is a compound in which all of the hydrogen atoms are substituted with fluorine atoms in a hydrocarbon which may contain an etheric oxygen atom. The hydrocarbon is a linear, branched or cyclic, saturated or unsaturated hydrocarbon.
Since perfluorocarbon has high polymerizability and can form a film on the surface of the article to be treated in a short time, it preferably has a carbon-carbon double bond. 2-6 are preferable and, as for carbon number of perfluorocarbon, 2-4 are more preferable from the surface of cost.
The perfluorocarbon is preferably one that has a low global warming potential and easily generates CF ₂ carbene that contributes to film growth.
Also, the greater the abundance ratio (F / C) of fluorine atoms to carbon atoms in perfluorocarbon, the better the oil repellency of the resulting film. In the present invention, in order to obtain good oil repellency, F / C is preferably 1.5 or more, and more preferably 2.0 or more.

Examples of preferred perfluorocarbons include tetrafluoroethylene, hexafluoropropylene, hexafluoropropylene oxide (HFPO), and PPVE, PMVE, AVE, BVE, c-C4F8 and C5F8 represented by the following formula.
Of these, tetrafluoroethylene and hexafluoropropylene are particularly preferable from the viewpoints of polymerizability and cost.
Perfluorocarbons may be used alone or in combination of two or more.

<(B) Oxygen-containing compound>
As the oxygen-containing compound, a compound having an oxygen atom and having neither a C—H bond nor a halogen atom is used. The oxygen-containing compound liberates oxygen atoms in the plasma. Moreover, since it has neither a C—H bond nor a halogen atom, it is preferable in that hydrophilicity can be imparted while suppressing a decrease in oil repellency of the film.
From the viewpoint of cost, those selected from the group consisting of oxygen, ozone, carbon dioxide, water, nitric oxide, nitrogen dioxide, sulfur dioxide and sulfur trioxide are more preferred. Oxygen is particularly preferable from the viewpoint of ease of handling. One oxygen-containing compound may be used alone, or two or more oxygen-containing compounds may be used in combination.
In view of polymerizability, cost, and ease of handling, it is particularly preferable that (A) the perfluorocarbon is tetrafluoroethylene or hexafluoropropylene, and (B) the oxygen-containing compound is oxygen.

<Production method>
In the method for producing an article of the present invention, a film is formed on the surface of the article to be treated by performing discharge treatment in an atmosphere containing (A) perfluorocarbon and (B) an oxygen-containing compound. The process of carrying out. It is preferable that (A) perfluorocarbon and (B) oxygen-containing compound exist in the form of a gas in the atmosphere of the discharge treatment.
Thereby, an article in which a film having hydrophilic oil repellency is formed on the surface is obtained.

“Hydrophilic oil repellency” in this specification means that the contact angle of water, which is an index of hydrophilicity, is 40 ° or less, and the contact angle of n-hexadecane, which is an index of oil repellency, is 25 ° or more. Say. A smaller water contact angle means higher hydrophilicity, and a larger n-hexadecane contact angle means higher oil repellency.
The values of the contact angle of water and the contact angle of n-hexadecane in this specification are values obtained by a semi-processed measurement method standardized in JIS-R3257.
When the contact angle of n-hexadecane is 25 ° or more of the film formed on the surface of the article, dirt is hardly attached and good antifouling property is obtained. In order to obtain higher antifouling properties, the contact angle of the n-hexadecane is preferably 30 ° or more, more preferably 40 ° or more.
When the contact angle of water in the film is 40 ° or less, the easy-cleaning property that the attached dirt can be easily removed by wiping or washing with water becomes good. In order to obtain better washing properties and excellent antifogging properties, the contact angle of water is preferably 30 ° or less, more preferably 22 ° or less.

The degree of hydrophilic and oil repellency of the film, that is, the contact angle of water and the contact angle of n-hexadecane is determined by the ratio of the number of oxygen atoms to the number of fluorine atoms (oxygen atoms) Number / number of fluorine atoms, hereinafter referred to as “O / F ratio”). As the O / F ratio increases, the hydrophilicity of the film increases and the oil repellency decreases. As the O / F ratio decreases, the oil repellency of the film increases and the hydrophilicity decreases. The O / F ratio can be controlled by adjusting the type and amount of (A) perfluorocarbon and (B) the type and amount of oxygen-containing compound supplied to the discharge treatment atmosphere.
Even if the O / F ratio is constant, the values of the contact angle of water and the contact angle of n-hexadecane can vary depending on the configuration of the apparatus performing the discharge treatment and the discharge conditions.

Therefore, depending on the device configuration, (A) the type and supply amount of perfluorocarbon, (B) the type and supply amount of oxygen-containing compound, and discharge so that the desired hydrophilic oil repellency can be obtained in the film to be obtained. It is preferable to set conditions.
For example, a high frequency power source of 13.56 MHz is used as a discharge power source, a discharge device using a capacitively coupled parallel plate is used, (A) hexafluoropropylene is used as perfluorocarbon, and (B) oxygen is used as an oxygen-containing compound. When the glass surface is treated with the electric power during the discharge treatment in the range of 10 to 30 W, in order to form a film having good hydrophilic oil repellency, the O / F ratio is 0.05 to 0.5. The range is preferable, and the range of 0.1 to 0.4 is particularly preferable.

In the atmosphere during the discharge treatment, in addition to (A) perfluorocarbon and (B) oxygen-containing compound, an inert gas such as argon, helium and neon, and other gases such as nitrogen may be present.
In order to form a film having good hydrophilic oil repellency, the total content of (A) perfluorocarbon and (B) oxygen-containing compound in the atmosphere is preferably 50 mol% or more, and 100 mol % Is more preferable.

(Discharge conditions)
The discharge treatment method in the present invention is not particularly limited, and for example, corona discharge (spark discharge), glow discharge, and the like can be applied. Glow discharge is more preferable. In either case, the surface to be processed is exposed to a gas atmosphere, and a discharge treatment is performed by applying a high-frequency voltage between the electrodes. The discharge form can be discharged continuously or in pulses.
The pressure of the discharge treatment atmosphere in the present invention is preferably 10 ⁴ Pa or less, and more preferably 10 ³ Pa or less. When the pressure of the atmosphere is 10 ⁴ Pa or less, the discharge stability is good. The lower limit of the atmospheric pressure of the discharge treatment is not particularly limited as long as it is in a range where good discharge is performed. For example, it is 1 Pa or more.
For example, a high frequency power source of 13.56 MHz is used as a discharge power source, a discharge device using a capacitively coupled parallel plate is used, (A) hexafluoropropylene is used as perfluorocarbon, and (B) oxygen is used as an oxygen-containing compound. When the surface of the glass is treated in an atmosphere having an O / F of 0.25 with a power during discharge treatment in the range of 10 to 30 W, in order to form a film having good hydrophilic oil repellency, The pressure is preferably in the range of 25 to 35 Pa.

The thickness of the film formed by the discharge treatment is preferably 2 μm or less. When the film thickness is 2 μm or less, there is an advantage that the durability of the film is improved and the manufacturing cost is reduced. 100 nm or less is more preferable. The lower limit of the film thickness is not particularly limited, but is preferably 1 nm or more and more preferably 10 nm or more from the viewpoint of preventing the occurrence of pinholes (portions where no film is formed on the substrate).
The film thickness can be controlled by the discharge conditions, and can be adjusted by, for example, the discharge treatment time.

According to the manufacturing method of the present invention, a film containing (A) a monomer unit derived from perfluorocarbon and (B) an oxygen atom (O) derived from an oxygen-containing compound is formed on the surface of the article to be treated. The The film has hydrophilic oil repellency. This is considered that hydrophilic oil repellency was expressed by oxygen being taken into the fluorocarbon film expressing oil repellency. Further, since the hydrophilicity of the film increases as the O / F ratio in the discharge treatment atmosphere increases, it is estimated that some or all of the oxygen atoms (O) in the film form a hydrophilic group.
In addition, since the production method of the present invention can control the degree of hydrophilicity and oil repellency of the film, it can form a film having hydrophilic oil repellency and antifogging properties.
Furthermore, since the film is formed by a discharge treatment in an atmosphere containing (A) perfluorocarbon and (B) an oxygen-containing compound, a conventional hydrophilic oil-repellent layer requiring a liquid phase coating step and a drying step The process is simple compared to the method of forming the film. In addition, since a chemical bond is generated between the surface to be processed and the film, the adhesion of the film is good and the durability is excellent.

  Since the article obtained by the present invention has a film having hydrophilic oil repellency on the surface, oil stains are difficult to adhere. Furthermore, the oil dirt once adhered can be easily wiped off, and the adhered dirt can be easily removed by washing with water. Preferably, excellent antifogging properties are also obtained. In addition, since the film is excellent in durability, a decrease in hydrophilic oil repellency due to wiping or friction is suppressed, and antifouling properties, easy cleaning properties, and antifogging properties are maintained well.

As the article in the present invention, an article requiring antifouling properties and easy washing properties, or an article requiring antifouling properties, easy washing properties and antifogging properties are suitable.
Specific examples of the article include wallpaper interiors such as wallpaper, kitchen interiors, bath tubs, and inner walls of water pipes; windows for cars and houses; mirrors; solar cell covers; display cover films; Contact lenses; tubules such as medical catheters.
In addition, because it provides excellent antifouling properties, easy cleaning, and hydrophilicity, surfing boards such as windsurfing boards and bodyboards; yachts such as pleasure boats, yachts, jet skis, and power boats; swimsuits for swimming; It is also suitable for marine screws.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.
FIG. 1 is a schematic configuration diagram of an apparatus used in the following examples. The apparatus of this example is generally configured as follows.
An upper shower head electrode 7 and a lower electrode 8 made of parallel plate electrodes are disposed in the vacuum chamber 5 so as to face each other. The upper shower head electrode 7 is connected to a high frequency power source 6 of 13.56 MHz, and the lower electrode 8 is grounded, so that low temperature plasma can be generated between the electrodes 7 and 8. An article to be processed 10 is detachably fixed on the surface of the lower electrode 8 facing the upper showerhead electrode 7. The upper showerhead electrode 7 also serves as a gas supply means. The upper showerhead electrode 7 includes (A) a perfluorocarbon supply means 3 provided with a flow meter and (B) an oxygen-containing compound supply means provided with a flow meter. 4 is connected. In addition, a number of gas ejection holes are provided on the surface of the upper shower head electrode 7 facing the lower electrode 8 so that gas can be supplied in a shower shape toward the article to be processed 10 on the lower electrode 8. It has become. Reference numeral 9 in the drawing denotes an exhaust means provided with a vacuum pump.

(Examples 1-9)
Using the apparatus of FIG. 1, a film was formed on the surface of glass (article to be treated).
First, a glass 10 having a thickness of 1 mm was placed on the lower electrode 8 and evacuated with a vacuum pump until the inside of the vacuum chamber 5 became 0.1 Pa or less. Next, after adjusting the distance between the upper showerhead electrode 7 and the lower electrode 8 to 5 cm, while simultaneously supplying hexafluoropropylene (HFP) gas and oxygen gas from the upper showerhead electrode 7 under the conditions shown in Table 1. Discharge treatment was performed. HFP gas and oxygen gas are supplied into the chamber 5 in a mixed state. “O / F” in Table 1 represents the ratio between the number of oxygen atoms and the number of fluorine atoms in the mixture of HFP gas and oxygen gas supplied into the chamber.
Subsequently, after the inside of the vacuum chamber 5 was purged with air, the discharge-treated glass was taken out. The water contact angle and the contact angle of n-hexadecane on the treated surface of the obtained glass were measured by a method standardized in JIS-R3257 (product of Kyowa Interface Chemical, product name; CA-X150). It measured using. The results are shown in Table 1.

(Comparative Examples 1 and 2)
A film was formed in the same manner as in Example 1 except that the discharge treatment was performed while supplying either HFP gas or oxygen gas into the chamber 5 under the conditions shown in Table 1. Table 1 shows the measurement results of the contact angle.
(Comparative Example 3)
A film was formed in the same manner as in Example 1 except that the discharge treatment was performed while supplying ethylene gas into the chamber 5 instead of HFP under the conditions shown in Table 1. Table 1 shows the measurement results of the contact angle.

The following evaluation was performed about the processed article (glass) in which the film | membrane was formed with the method of the said Example and comparative example.
[Membrane composition]
With respect to the processed articles obtained in Examples 8 and 9, the surface layer portion of the surface to be processed was subjected to X-ray photoelectron spectrometer (XPS, manufactured by ULVAC-PHI, Quantera), and the monochromatic AlKα ray was applied to the X-ray source. It was used at 40.3 W, the photoelectron detection area was 0.2 mmφ, the photoelectron detection angle was 45 degrees, and the path energy was 224 eV. The film composition was calculated by observing 1s peaks of oxygen atoms, carbon atoms and fluorine atoms from the obtained wide spectrum and calculating the respective atomic ratios.
Further, the 1s peak of the carbon atoms is observed by narrow spectrum, -CF ₂ near 292 nm - was confirmed peaks derived from.

As a result of the film composition analysis, the treated article of Example 8 was carbon (C): 47.4 mol%, oxygen (O): 9.9 mol%, and fluorine (F): 42.8 mol%. Further, in the measurement by XPS, a portion where the substrate surface was visible was not recognized.
In Example 9, it was C: 56.5 mol%, O: 16.9 mol%, F: 26.6 mol%. In the XPS measurement, a portion where the substrate surface was visible was observed.

[Film thickness]
As the evaluation of the film thickness, for the processed articles obtained in Examples 7, 8, and 9, after partially peeling the surface layer portion of the surface to be processed, the step between the peeled portion and the non-peeled portion was determined by atomic force. It measured with the microscope (AFM, Seiko Instruments company make, Nanopics2000).
As a result, Example 7 was 12 nm, Example 8 was 37 nm, and Example 9 was 35 nm.

[durability]
As an evaluation of durability, a wipe test was performed by reciprocating 20 times while pressing Kimwipe “S-200” (trade name, manufactured by Crecia Co., Ltd.) with 4.9 N on the surface of the film formed on the surface to be processed. . The n-hexadecane contact angle of the rubbed portion was measured in the same manner as described above. Table 1 shows the measurement results of the contact angle.
If the film is removed by the wipe test, the glass surface is exposed, so that it exhibits lipophilicity after the wipe test. If the difference in the contact angle of n-hexadecane before and after the wipe test is within 10 °, it is determined that the durability is satisfactory without any practical problem, and is indicated in the table as “◯”.
In addition, about Comparative Examples 1-3, since the formed film | membrane did not have favorable hydrophilic oil repellency, durability evaluation was not performed.

[Easy cleaning (dry type)]
As an evaluation of easy cleanability by dry cleaning, oleic acid is adhered as a stain to the surface of the film formed on the surface to be treated, and wiped with a cellulose nonwoven fabric (trade name: Bencott M-3, manufactured by Asahi Kasei Co., Ltd.) The ease of removal was determined visually. The judgment criteria were as follows. The results are shown in Table 1.
◯: The oleic acid could be completely wiped off.
Δ: An oleic acid wiping trace remained.
X: The oleic acid could not be wiped off.
In addition, ○ can be used practically.

[Easy cleaning (washing)]
As an evaluation of easy cleaning by washing with water, oily magic (Zebra, Mackey extra fine black "MO-120-MC-BK") is attached as dirt on the surface of the film formed on the surface to be treated. Ultrasonic waves were irradiated for 2 minutes while impregnating in water, and the ease of removing the dirt was visually determined. The judgment criteria were as follows. The results are shown in Table 1.
◯: The oily magic was completely removed.
Δ: Some oily magic remained.
X: Oily magic could not be removed.
In addition, ○ can be used practically.

[Anti-fogging property]
For the evaluation of anti-fogging properties, blow on the surface of the film formed on the surface to be treated, ◎ if it is not white and cloudy, ○ if it blows and turns white but immediately becomes transparent, ○ blows and blows white The case where it took time to become transparent was marked with x. The results are shown in Table 1.
In practice, ◎ and ○ can be used.

As shown in Table 1, in Examples 1 to 9 in which the discharge treatment was performed in an atmosphere containing HFP gas and oxygen gas, the glass had a hydrophilic surface with a water contact angle of 40 ° or less on the glass surface, and n -An oil-repellent film having a contact angle of hexadecane of 25 ° or more was formed.
On the other hand, in Comparative Examples 1 and 2 in which discharge treatment was performed in an atmosphere containing only HFP gas or oxygen gas, and in Comparative Example 3 using ethylene gas which is a non-fluorine compound gas instead of HFP gas, hydrophilicity and A film having both oil repellency was not formed. The film formed in Comparative Example 1 was water and oil repellent and was inferior in easy cleaning and antifogging properties. The films formed in Comparative Examples 2 and 3 were hydrophilic and lipophilic and had good antifogging properties but were not easily washed.

It is the schematic block diagram which showed the example of the apparatus used for the discharge process concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Perfluorocarbon supply means 4 ... Oxygen containing compound supply means 5 ... Vacuum chamber 6 ... High frequency power supply 7 ... Upper shower head electrode 8 ... Lower electrode 9 ... Exhaust means

Claims (6)

  The surface of the article to be treated made of a material selected from the group consisting of glass, ceramics, and plastics has (A) perfluorocarbon and (B) oxygen atoms, and has neither C—H bonds nor halogen atoms. A method for producing an article comprising a step of forming a film on the surface of the article to be treated by performing a discharge treatment in an atmosphere containing an oxygen-containing compound.   The method for producing an article according to claim 1, wherein the (A) perfluorocarbon has a carbon-carbon double bond.   The oxygen-containing compound (B) is at least one selected from the group consisting of oxygen, ozone, carbon dioxide, water, nitric oxide, nitrogen dioxide, sulfur dioxide, and sulfur trioxide. Manufacturing method of the article.   The method for producing an article according to any one of claims 1 to 3, wherein the (A) perfluorocarbon is tetrafluoroethylene or hexafluoropropylene, and the (B) oxygen-containing compound is oxygen.   The method for producing an article according to any one of claims 1 to 4, wherein the film has a thickness of 2 µm or less. The method for producing an article according to any one of claims 1 to 5, wherein a contact angle of water in the membrane is 40 ° or less and a contact angle of n-hexadecane is 25 ° or more.

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